CLASSIFICATION OF THE TISSUES. 



27 



The lymph appears colorless and clear as water. Taken 

 from the smallest vessels, it may be without cells. It con- 

 tains large quantities of them when drawn from the larger 

 vessels, especially just after the passage of the latter through 

 lymphatic glands or allied structures. Nevertheless, it is infi- 

 nitely less rich in cells than the blood. They are the same 

 lymphoid cells we became acquainted with in the blood (Fig. 

 31) ; further description is therefore unnecessary. 



The lymph presents nothing further. In the chyle, on the 

 contrary — and they cause the cloudy or whitish appearance 

 of the fluid — we meet with innumerable infinitely fine dust- 

 like molecules. With a strong magnifying power they show a 

 peculiar, dancing, driving about, the so-called Brunonian 

 molecular movement. But there is nothing strange in this. 

 It is natural to all very small bodies suspended in water, 

 small particles of fat, the smallest crystals, carmine granules, 

 and the like. These dust-like particles consist of fat, sur- 

 rounded by a very thin albuminous covering. 



Red blood corpuscles may be met with in the lymph and 

 chyle as incidental constituents, and occasionally as transition 

 forms. I have seen the latter in the thoracic duct of the 

 rabbit. 



Red blood cells, pressed out from the blood-vessels, may 

 also finally reach the lymphatics. There is no doubt that the 

 actively emigrated colorless blood cells often penetrate these 

 passages, and thus again commence the journey back into the 

 blood. 



